I have desktop HP pavilion media center with windows vasta home preimum. 3g ram and 500gb hard drive.when I turn it on after while says window has been shut down to prevent damage to ur computer. windows does not start ,giving error. then I tried to system recovory to bring it to factory condtion,but when system recovoy had reached to 40% then it says windows has been shut down to prevent............ I could not done recovory. I think some files are deleated. now says windows does not start because missing or corropting files. then I tried to system recovory from dices ,it stoped at 40% again. but should I do ? window does not start .thanks